Ben Stiller, Robert Downey Jr., Nick Nolte and Jack Black star in "Tropic Thunder," an action movie spoof about actors surviving in the middle of a jungle.

"Tropic Thunder" has sparked more chatter before its release than most movies ever provoke. And almost none of the controversy has anything to do with the movie itself.

Director Damien Cockburn (Steve Coogan) is struggling to complete his big-budget war movie. Mostly because he has lost control of his ego-stuffed cast.

Has-been action star Tugg Speedman (Ben Stiller) is a bad actor and butts heads with his Oscar-winning co-star Kirk Lazarus (Robert Downey Jr.), who prepares for his role as a black soldier so completely that he has doctors change his skin pigment. Jeff Portnoy (Jack Black), famous only for farting in mindless comedies, struggles to keep his drug addiction a secret. Rapper turned actor Alpa Chino (Brandon T. Jackson) fights to balance Lazarus' stereotypical portrayal of blacks and hides a secret of his own. The only professional in the bunch is an unknown, up-and-coming character actor, Kevin Sandusky (Jay Baruchel).

Hounded by his alpha-male producer, Les Grossman (Tom Cruise), and willing to go to any length to capture "the reality of war," Cockburn and his wacko technical adviser, Four Leaf Tayback (Nick Nolte), plant hidden cameras throughout the jungle and drop the cast in the middle of nowhere. The pampered actors must survive on their own, fight a real guerilla drug cartel and stage a climactic rescue.

It's a brilliant movie-within-a-movie that blurs the lines between the actors in the comedy we're watching and the roles they play in the war movie they're trying to make. The plot is completely recycled, but for good reason. As "Shaun of the Dead" did with the horror genre, "Tropic Thunder" skewers every war movie cliché.

And yet, "Tropic Thunder" is also loaded with surprises and goes well beyond the average spoof. Something unexpected happens in virtually every other scene.

But the genre parody is mostly a vehicle for the cast to poke fun at, well, themselves. Because "Tropic Thunder" is, more than anything, an outstanding satire of self-involved Hollywood actors and producers.

Downey simultaneously parodies the token minority roles that have always been a staple of action movies and method actors who take their preparation to ridiculous extremes in an effort to build credibility.

Cruise (and I am as shocked as you) pulls off the most surprising role in a 2008 film. He embodies his over-the-top uber-producer with an abandon he has previously shown only in "Magnolia."

The whole movie is fearless in its quest to make us laugh, which is refreshing.

The language and humor are occasionally as crude as "Superbad" and other Judd Apatow movies, but it's also as smart as anything Stiller and friends have ever done.

Is it offensive? Probably. But the bull's-eye remains consistently on Hollywood egos. The actors are the butt of the joke at all times.

Is it funny? "Tropic Thunder" is without doubt the funniest damned movie I'll see this year. I will respectfully listen and sympathize with any groups who happen to complain about it, but I won't lie: I laughed out loud at "Tropic Thunder" a lot.

Jeff Marker is a media studies professor at Gainesville State College.